CD8 + T-cells play a crucial role in eradicating viral infections. The focus of this project is twofold. First, to study mechanisms that viruses use to subvert CD8 + T-cell responses and second, to understand how primary CD8 + T-cells are stimulated. Despite the importance of T-cells, little attention has been paid to the ability of vaccines to induce CD8 + T-cell memory. For viruses in which traditional vaccine approaches have not been successful, it is hoped that induction of CD8 + T-cell memory will enhance immunity. To induce optimal CD8 + T-cell responses to vaccines it is necessary to understand how primary CD8 + T-cells are stimulated. This project aims to answer the following questions; 1. Following a virus infection in what anatomical location are primary TCD8+ cells stimulated (local sites of infection, lymph nodes, spleen)? 2. What type of cell presents antigen to primary CD8 + T-cells? 3. Is the antigen presenting cell infected, or does it present viral proteins obtained from infected cells? 4. How does these answers to questions 1-3 vary between different antigens encoded by the same virus and the same antigen encoded by different viruses?